1. Field of the Invention
This invention relates to a camera of the kind arranged to be capable of using a film cartridge which is provided with a so-called DX code consisting of encoded film information such as an ISO sensitivity value, the number of photographable frames, etc. and more particularly to a film code reading device arranged to read out the DX code and a camera system having the reading device.
2. Description of the Related Art
Heretofore, a camera of the kind arranged to be capable of using a film cartridge which is provided with the DX code has been arranged to have such film data as an ISO sensitivity value, the number of frame portions available for photographing, etc. automatically set when the camera is loaded with the film. The camera of this kind is of course capable of using also a film contained in a cartridge not having the DX code. In that event, however, the ISO sensitivity information which is indicated on the film cartridge must be supplied to the camera by a manual operation. Therefore, in cases where the camera is loaded with a film without confirming the presence or absence of the DX code on the film cartridge, a photographing operation might be performed with an inapposite exposure if the film cartridge happens to have no DX code. To solve this problem, an arrangement to make a display when the camera is loaded with a film cartridge having a DX code has been proposed, for example, as disclosed in U.S. Pat. No. 4,200,371. However, the camera under this U.S. patent is arranged to merely display whether the film in use is provided with the code information and is not arranged to give any warning when the film code is not correctly read out. Further, known cameras of the kind reading out the film information from a film cartridge having the DX code have been arranged to read out the information borne by everyone of all the bits included in the code pattern as disclosed, for example, in U.S. patent application Ser. Nos. 757,136 and 770,157, U.S. Pat. No. 4,512,643, etc. This code reading method has necessitated use of many contact pieces and optical members for the code reading operation. Meanwhile, commercial film products are generally arranged to permit 12, 24 and 36 frame exposures with these different photographable numbers of frames indicated in three-bit code patterns within the DX code. While three bits are thus used for the code pattern representing the number of frames, it is only two of the three bits that are actually indicating the photographable number of available frames of the general commercial film products. Therefore, the code indicative of the available number of frames can be adequately read out by reading only two of the three bits.
Cameras of another kind arranged to automatically rewind the film after completion of photographing on a predetermined number of frame portions of film read out from the DX code provided on the film cartridge have been known, for example, from Japanese Laid-Open Patent Application Nos. Sho 60-37536 and Sho 60-115917. With the camera arranged in that manner, however, in the event of incorrect DX code reading, such as misreading a film of 36 exposures for a film of 24 exposures, for example, the film would be prematurely rewound upon completion of a 24th exposure thus leaving the remaining portion of the film unused.
Meanwhile, since films of 36 exposures are the longest of film products used in general, the above-stated inconvenience may be avoidable by setting a camera for a total number of 36 frames. With the number of frames thus set at 36, in the event of the above-stated inaccurate code reading, the premature film rewinding operation can be effectively prevented. However, in case that the camera is loaded with a film for only 12 exposures, the above-stated arrangement to automatically set the camera for a total number of 36 frames for the generally used film products of 36 exposures presents another problem because the film is not rewound after only 12 exposures. To solve this problem, it becomes necessary to have a film end detecting device additionally arranged within the camera in a manner as disclosed, for example, in Japanese Laid-Open Patent Application Nos. Sho 58-83829 and Sho 58-83828.